Afterbeat

Set in 207X, a mysterious disease called "LNNS" has been ravaging the world. A lone AI researcher, Anna Schroeder, attempts to find the cure with her trusty supercomputer companion HAL. Stumbling upon various “Projects,” the duo decides to investigate the efficacy of a cure using a pulse/rhythm-based interface.

Résumé

A musical bullet-hell where all things beautiful are deadly. Dodge well little nanobot, you don't have much time.